B767 flight crew has an altitude excursion in uuwv airspace.

Attributes
ACN	699871
Time
Date	200606
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : uuee.airport
State Reference	FO
Altitude	msl single value : 33300
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B767 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level descent : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp pilot : commercial pilot : multi engine pilot : private
Experience	flight time last 90 days : 210 flight time total : 3500 flight time type : 1500
ASRS Report	699871
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera other controllera
Resolutory Action	controller : issued advisory flight crew : returned to assigned altitude
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous

Narrative:

I was the first officer (PF) on air carrier X to uuee. Just past spb; moscow center cleared us to descend to 8100 meters; provide our estimate to nukol and to report nukol. The captain acknowledged and repeated this clearance back. Both the captain and myself heard this clearance clearly and I began my descent from 11100 meters to 8100 meters. Approximately 4000 ft into the descent the controller told us to climb back to 11100 meters. We asked if he had cleared us to 8100 meters but due to the language barrier he did not understand. There were no TA's or other known aircraft in our vicinity. No other significant events followed.

Original NASA ASRS Text

Title: B767 FLT CREW HAS AN ALT EXCURSION IN UUWV AIRSPACE.

Narrative: I WAS THE FO (PF) ON ACR X TO UUEE. JUST PAST SPB; MOSCOW CTR CLRED US TO DSND TO 8100 METERS; PROVIDE OUR ESTIMATE TO NUKOL AND TO RPT NUKOL. THE CAPT ACKNOWLEDGED AND REPEATED THIS CLRNC BACK. BOTH THE CAPT AND MYSELF HEARD THIS CLRNC CLRLY AND I BEGAN MY DSCNT FROM 11100 METERS TO 8100 METERS. APPROX 4000 FT INTO THE DSCNT THE CTLR TOLD US TO CLB BACK TO 11100 METERS. WE ASKED IF HE HAD CLRED US TO 8100 METERS BUT DUE TO THE LANGUAGE BARRIER HE DID NOT UNDERSTAND. THERE WERE NO TA'S OR OTHER KNOWN ACFT IN OUR VICINITY. NO OTHER SIGNIFICANT EVENTS FOLLOWED.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.